To connect up your lovely FT-817/857/897 to
a PC you have a number of options. For the serial connection you can go
ahead and obtain a CT-62 from YAESU.

Alternatively you can make up your box with
a level converter and cable using schematic below.Reason for using this box is to get the crossover
usage from both ACC and DATA to a serial interface and having option for
band data and ALC from the same box without having to swap cables.

Go on and read about the details.

As you can see you only need 3 NPN transistors and
some resistors to make this happen. Included you also have a transistor
keying CW och PTT using the serial DTR line. Personally I prefer using
the RTS-pin for the PTT-control. In a newer release I now use the TTL <->
RS232 level converter MAX232. Reason for that is that I now can use the
same converter also to control a ICOM (IC-703) using the CI-V-interface.

The pinout of the YAESU ACC connector is as follows
( taken from the FT-817 manual by YAESU).

The DATA-connector on the FT-817/857 and 897 seems
to conform with the defacto-standard for connecting up rigs of today to
TNC:s, FSK-units and PC-soundcards. Same connector and pinout is also on
my ICOM IC-703.
Pin 1 from the DATA 6 pin mini-DIN is connected
to the speaker or line out, pin 4 is connected to the mik or line in of
the PC:s soundcard. The rigs PTT (pin2) is keyed from the PC:s serial DTR-line
using the switch in the scematics above. See how great this all fits together
!!?

The DATA and ACC-connectors on the back are connected
out to a common 15 pin high density D-sub-connector (the VGA-screen type)
on the diecast ALU-box. The box is housing the transistors from the schematics
above. Audio is connected up using RCA/phono-connectors. The serial connector
is a standard 9 pin D-sub. I also have a option connecting up to a automatic
antennaswitch using the band-data information (see ACC-connector).
Reason for using this box is to get the crossover
usage from both ACC and DATA to serial connector and having option for
band data and ALC from the same box without having to swap cables.

Here you hace a closeup of the ALU-box 50x36x30 (WxDxH).
You see the ugly wiring design. The band data is taken out trough a 3.5
mm plug.